Source: https://mokxi.com/vs/qucs-s Updated: 2026-10-04 Comparison # Mokxi and Qucs-S, compared fairly Mokxi is a free, browser-based alternative to Qucs-S for SPICE work on machines that cannot install a desktop simulator. It runs SPICE decks on an engine checked against ngspice and runs breadboard circuits live, without Qucs-S’s choice of engines or its RF analyses. Qucs-S is a free, open-source circuit simulation program with a Qt interface over several engines: ngspice, Xyce, SpiceOpus, and Qucsator for RF work. It runs on Linux, Windows, macOS and FreeBSD. Mokxi is a free circuit and firmware simulator in a browser tab that runs SPICE decks on its own engine. Here is where each one is the right answer. Last checked September 2026 Start building free or see the plans - 228 parts on the bench - 31 boards running now - 1.00x real time, on every board Click to open it in the editor Running here on our own RISC-V core, on the machine in front of you. The Mokxi editor running an RL filter on the bench, with a signal generator driving it and a two-channel oscilloscope on both ends. ## Where Qucs-S leads These are the strongest reasons to choose Qucs-S today. - Free and open source under the GPL-2.0, a desktop program that works offline on Linux, Windows, macOS and FreeBSD. - A choice of engines: ngspice, which reads most industrial SPICE models, Xyce, SpiceOpus, and Qucsator for RF and microwave circuits. - Analyses Mokxi does not have, among them S-parameters, harmonic balance, distortion, pole-zero, sensitivity and spectrum analysis. - Schematic capture tied to all of those engines, so one drawing can be run on whichever suits the job. ## Where Mokxi leads These are working parts of Mokxi you can open and test for yourself. - Runs in a browser tab with nothing to install, including on a school Chromebook. - SPICE decks run in the editor: .op, .tran, .ac, .dc, .tf, .noise and .meas with subcircuits, parameters and model cards, on an engine checked against ngspice on 42 benchmark circuits. - A breadboard with bench instruments wired in as parts: a signal generator, a two-channel oscilloscope, a multimeter and a bench supply. - Microcontrollers on the same canvas: 31 boards running compiled C++, so a circuit and the code that drives it are tested together. ## Side by side Last checked September 2026. If anything here has gone stale, that is our mistake and we want to know. | Mokxi | Qucs-S Aimed at | Breadboard circuits, instruments and firmware | Analog and RF circuit simulation Runs in | A browser tab, including on Chromebooks | A Linux, Windows, macOS or FreeBSD install Price | Free; paid plans for classes and more room | Free and open source Engines | Its own SPICE engine, checked against ngspice | ngspice, Xyce, SpiceOpus or Qucsator Analyses | Operating point, transient, AC, DC sweeps, transfer function, noise and .meas | AC, DC, transient, noise, distortion, pole-zero, S-parameters, harmonic balance and more Open source | No | Yes Sources for Qucs-S - Qucs-S: home page (engines, analyses, platforms) - Qucs-S on GitHub (license, platforms) ## Which one should you use Straight answers. Where the other one is the right call, we say so. ### You design RF or microwave circuits Qucs-S, with Qucsator. Mokxi has no RF analyses. ### You need a particular engine such as Xyce, or models only ngspice reads Qucs-S. ### Your class works on Chromebooks Mokxi runs there with nothing to install. ### You want a circuit and the microcontroller driving it tested together Mokxi. ## Compare the other options The same straight comparison for the tools teachers, students and makers also consider. Mokxi vs Tinkercad Circuits Mokxi vs Wokwi Mokxi vs Proteus Mokxi vs Fritzing Mokxi vs SimulIDE Mokxi vs Falstad (CircuitJS) Mokxi vs Multisim Mokxi vs LTspice Mokxi vs Logisim-evolution Mokxi vs CircuitVerse Mokxi vs Digital Mokxi vs EveryCircuit Compare every simulator ## In short Should I use Mokxi if you design rf or microwave circuits? Qucs-S, with Qucsator. Mokxi has no RF analyses. Should I use Mokxi if you need a particular engine such as xyce, or models only ngspice reads? Qucs-S. Should I use Mokxi if your class works on chromebooks? Mokxi runs there with nothing to install. Should I use Mokxi if you want a circuit and the microcontroller driving it tested together? Mokxi. ## Try it yourself A comparison page is somebody else’s opinion. Open the editor, press Run and make up your own mind. Start building free Open the editor Free forever. Every board and part. Saves your projects. Works on Chromebooks.